Drawing flat sheet glass



Jan. 11, 1927. E. FERNGREN DRAWING FLAT SHEET GLASS Filed Odt. 4. 1923 4 Sheets-Sheet 1 l N V E NTOR Enoch Z'fmgren BY ATTO RN EY 4 Sheets-Sheet 2 hm R INVENTOR 00:77?!

all

lhl

0/ &

Jan.

ATTORN Jan. 11, 1 927.

E. T. FERNGREN DRAWING FLAT SHEET GLASS Filed Oct. 4. 1923 4 Sheets-Sheet 3 INVENTOR ATTO R N EY fnoch TFerngren i8 I v BY Patented Jan. ll, 192?.

UNETEB STATES PATENT FFIQE.

ENOCH '1. FERNGREN, OF TOLEDO, 02-111), ASSIGNOE TO THE LIBBEY-GWEN'S SHEET GLASS COlilIPANY, 0F TOLEDO, OI-Ilt), A CORPORATION OF OHIO.

DRAWIIJG FLAT SHEET GLASS.

Application filed October This invention relates to in'iprovements in the art of drawing flat sheet glass, and more especially to an improved method of and apparatus for controlling the temperature conditions in the drawn sheet at an intermediate stage of the sheet formation.

The invention is more particularly designed for controlling the temperature of the sheet while it is still in a semi-plastic condition and is being deflected from vertical to a horizontal plane prior to the flat toning process. In the Colburn process of drawing flat sheet glass, as set forth or o);- ample in the patent to I. W. Colhnrn, 1,248,809, granted December 4, 1917, a sheet of glass is drawn upwardly from pool of molten glass, and while still somewhat plastic is deflected about a bending roller into the horizontal plane Where it is carried away through suitable drawing and flattening mechanism into the leer. It is essential that the temperature or the glass sheet, and of the bending roller, be very accurately continllcd, since ii the sheet or roller is too hot, the sheet will stick to the roller and be injured thereby, whereas if the roller or sheet is too cold, the bending process cannot be arried out without warping or breaking the sheet. Ordinarily, the roller is .eou'iewhat cooled internally by passing a cooling fluid, usually air, therethrough. A water cooler is positioned below the roller and adjacent the glass sheet, this cooler serving to cool the surfaces of the sheet and roller before they contact with one an0ther, and also serving to shield the lower surface of the roller from the heated air currents passing up from the molten mass of glass from which the sheet is drawn. The sheet, while still sufl'iciently plastic to be bent about the'roller, becomes so chilled during the bending process that it is necessary to reheat the sheet as it leaves the roller in order that it may be drawn away therefrom in flat form. For this purpose a pipe burner, consisting o'r' a longitudinal series of separate flames or bur ers arranged transversely of the sheet is positioned that the flames playupon the sheet just before it leaves the surface of the bend-- ing roller.

Due to various causes, such as change le air currents of different temperatures passing through the space about the drawn sheet and the inner structure of the machine, and

1923. Serial No. 666,478.

the dithculty of accu 'ately controlling the heating and cooling mechanism, hot or cold spots sometimes develop in the bending member or sheet, or both. These unequal temperature conditions will not only produce internal strains Within the sheet, but will set up lengthwise running thick and thin formations or waves in the sheet structure. While these variations in thickness are very minute, they are sufficient to distort light waves and adversely affect the optical properties of the sheet. These temperature variations, and consequent variations in sheet thickness, are also caused by non-homogeneous condi tions and varying temperature conditions in the molten glass from which the sheet is drawn, as well as the cooling effect of width maintaining devices used near the edges of the sheet.

For any or all of the above reasons the sheet may arrive at the bending roller and be deflected thereabout, while unequal local temperature conditions are present in different areas of the sheet from edge to edge thereof.

As the direction in which the sheet moves during the drawing operation is changed at the bending roll from the vertical into the horizontal run, there is set up a series of unlike tensions and strains in the glass of the rheet at the point of bend, due to the fact that the outside or upper surface of the sheet, in the relation of the sheet to the bending roll, is a greater distance from the point of rotation or center line of the roll, and thus this outer portion is compelled to stretch and yield considerably more than the inner surface ofthe sheet which is in contact with the roll. It all of the glass of the sheet as it bends, would have the same degree of plasticity and the same degree of thickness, this increase of stretching tension toward the outer surface of the sheet would very likely not cause any run like strains or stresses in the sheet, but at the present time, due to the now prevalent thicker and thinner formations and the different temperatures of these formations, the strains at the bending point are the cause of irregular Wavings-in the sheet, and a so considerable breakage in the leer, which the subsequent heating and flattening process has so far failed to entirely eliminate.

The pipe burner at present used for renoted above, since an apprordniately equal amount of heat is applied to all portions of the sheet. Furthermore, this type of burner may even create additional inequalities, due to the fact that the flame projected on the sheet by this series of burners is not entirely continuous, but consists of a series of separate spaced flames which do not always com pletely blend witl one another to form a single .sl eet ot flame of uniform intensity.

The general aim of the present invention is to locally control the ten'iperature ot' the glass sheet at all points longitudinally of the bending roller and t rnsvm'sely of "he sheet, so that unequal temperature conditions may he counteracted and eliminated, and the sheet given a uniform plasticity and temperature at all areas thereof.

One object of the invention is to provide a reheating burner that may produce an even and uniform sheet of flame across the entire width of the sheet. This is aocomplished by imparting a slight lengthwise reciprocating movement to the pipe burner so that the series of flames will be completely blended with one another.

burner which is bodily adjust: l or from the Sheet, and angular-l a to Vary as desired the angle oi conta the reheating flames with the glass shr- Another objec is to provide. rhea s controlling the intensuty, or completely shutting off, any desired portion of the burner, at any local ooint across the width of the sheet, so that the inten' ity of the reheat'ng' means may he varied or locally applied as the heat conditions in the sheet may require. Several n'ieanzaz For loc v conlicolling' the burners are hereinafter disclosed,

Another object of the invention is to provide an adjustable cooling means to be used beneath the bending; roller and adjacent that side of the sheet wh'ch contacts with inovahle a shield intensity Fig. l is a side elevation of the bending roll and reheating burner, together with the mechanism for snpporting and reciprocating; the burner.

Fig. 2 a side elevation of part or": the mechanism disclosed in Fig. 1, tie view being taken substantially looking from the right oi Fig. 1.

Fig. 3 is a central longitudinal section through that end of the iipe burner shown in F gs. 1 and 2.

Fig. i is a s inilar View of the opposite end of this pipe burner.

lr' ig. 5 is a pcrsoective oi, a portion or? the burner, portions being broken to disclose the regulating mechanism within the pipe.

Fig. (i is a cross-"ection through the burner tal-Lcn substantially on the lin 5- 6 of Fig. l.

Fig. 7 is a tevelopinent of the regula ng' sleeve within the burner pipe, illustratin the configuration of certain slots with which this sleeve may he provided.

Fig. 8 is an elevation of a burner renulating sleeve, and its operating Inechan in, which may be used on the outside of the burner pipe.

Fig. 9 is a partia plan view illustrating one oi the ways in which the reheating flames may be applied to the glas sheet.

30 is transverse section through the cooler which is used beneath the sheet and bending roller.

Fig. 11 is a horizontal section through this cooler taken substantially on the line ll-ll of Fig. 10.

Fig. 12 is a vertical section through this cooler taken substantially on the line 12l2 of Fig. 10.

Referring firs more particularly to Figs. 1, 2 and 9, the glass sheet 1 is drawn upwardly from the mass of molten glass 2 in a receptacle 3, and is then bent from the vertical into the horizontal. plane about the bending roller 4-, and carried away through a suitable form of drawing and flattening mechanism not here disclosed. The bending roll l is usually internally cooled in any suitable manner, as disclosed in the Colburn patent referred to above.

For reheating the sheet as it leaves the bending roller in the horizontal plane, preparatory to the flattening process. a pipe burner 5 is positioned parallel to and adjacent the bending roller 4. Combustible gas is fed into this pipe through suitable connections 6 adjacent one end thereof (see Figs. l and 8). and the pipe is rovided with a longitudinal series of spaced holes or ports '4' through which the may pass out to provide burners or flames S which play upon the surface of the glass sheet. As here shown, these holes 7 are arranged in spaced groups of three, the three holes slightly converging, as shown in Fi 6, so

that the resulting flames will impinge on one another and form a single broad flat flame substantially at the point of contact with the glass sheet 1. It is to be understood that the arrangement and spacing of the holes as here disclosed is merely one form of many that might be used with the features of the invention as hereinafter disclosed.

The burner 5 is carried adjacent its ends in bearing sleeves 9 and 10. Each of these sleeves is pivotally mounted, by means of screw-bolt 11, on a supporting plate 12 (see Fig. 1), the plate 12 in turn being adjustably mounted in a bracket arm 13 horizontally pivoted at 14 on a second vertically pivoted bracket 15. Bracket 15 is secured to the low-er end of a pin 16 mounted in vertical bearing 17, formed on a portion of the supporting framework. Bracketarm 13 has a lever extension 18 provided with a pin 19 adjustable in any one of a series of holes 20 in the supporting bracket 15. In this way the pipe burner 5 may be swung up or down to change its vertical position with relation to the bending roll 4. Supporting plate 12 is longitudinally adjustable by means of screw-bolt 21 in the end of bracket arm 13. By this means the pipe burner 5 may be adjusted toward or from the bending roll 4. An arm 22 keyed to one end of burner 5 carries a pin 23 adj ustable in any one of a series of sockets 24 in bearing 9. By this means the burner 5 may be angularly adjusted to change the inclination of the flames 8 with respect to the sheet and bending roller.

Since the series of separate spaced flames arranged transversely of the sheet. sometimes tail to blend sufficiently to provide an even sheet of flame of equal intensity at all points across the sheet width, but instead produce a series of alternating hot and cold spots, it is proposed to slightly reciprocate the burner pipe 5 so as to oscillate the flames projected from the several ports 7 and completely blend these flames with one another. Many different arrangements might be devised to produce this reciprocating movement, and the one about to be described is merely one example well adapted for pertorn'ling this function. A horizontal shaft 25 is carried in a tearing 26 projecting from the fixed framework of the machine. To one end of shaft 25 is removably secured a crankarm 27, on whose free end is a roller 28 normally resting on the fluted surface 29 ot cam disc 30. This disc 30 is freely pivoted on one end of roller 4 and may be keyed to this roller when desired. to rotate therewith. by means of sliding clutch member 31. It is to be understood that this operating cam 30 might be mounted on any one of the supporting rollers or driven shafts adjacent this portion of the sheet drawing 43 on the pin.

apparatus, as well as upon the bending roll 4. Slidably mounted on the opposite enl of shaft 25 is a crank-arm 32 which is adapted to be keyed to the shaft 25 by set-screw 33. The lower end of crank 32 is connected through a universal joint to one end of a link 34, the other end of this link being pivoted to a nut 35 mounted on screw shaft 36. Shaft 36 is supported in a pair of ears 37 and 38 projecting outwardly and downwardly from the supporting bracket 15. To the upper end of the supporting pivot 16 for bracket 15 is secured a crank-arm 39 whose outer end is pivoted to a pin or link 40, the other end of which is slidable through a fixed lug 41. A compression spring 42 surrounds pin 40 between lug 41 and a collar This spring 42 acts to normally swing the supporting bracket 15, and the burner 5 inwardly. or away from the observer, as viewed in F 1. As roller 28 rides up over the cams 29 on disc 30, the cranl'r-arm 32 will be swung outwardly, or toward the observer, as viewed in Fig. 1, and through the link connection 34 will draw the pivoted bracket 15 outwardly against the action of spring 42. In this manner the cam 30 and spring 42 will cooperate to give a reciprocating movement to the burner 5 suflicient to blend together the several individual flames 8 into one continuous sheet of flame. 3y adjusting nut 35 along the screw-shaft 36, and giving corresponding adjustment to crank 32 along the end or shaft 25, the effective lever arm on crank 15. may be varied to adjust the amount of throw or reciprocation imparted to the burner '5. This reciprocation may be stopped when desired. by unlocking clutch 31, or by disconnecting either of cranks 27 or 32 from shaft 25. ()r the parts may be locked in position, with roller 28 lifted from cams 29, by inserting a locking pin through perforated cars 90 and 91. on bracket 15 and bearing 17, respectively.

Means are provided to vary the intensity of the reheating flame, locally across the sheet, in accordance with the hot or cold streaks that may occur in the glass sheet. In. general, this is accomplished by selectively obstructing or entirely shutting oil the flow of gas through some oi the ports 7. This may be accomplished in various ways, and several different mechanisms are here shown which may be used either separately or concurrently to accomplish the desired result.

Referring now especially to Figs. 3 to 8, inclusive, a sleeve 44 is mounted within and closely fitting the pipe 5. This sleeve 44- is somewhat shorter than the pipe 5 and is capable of being given both a longitudinal and rotary adjustment within the pipe. As shown in Fig. 3, one end of pipe 44 is connected through the stuffing-boxes 45 with a 1 smaller sleeve 46 extending out through the end of the burner. 'lhe stutlingboxes l are to prevent the escape of gas at this end oi? the burner assembly. A crank-arm ll or other suitable handle, is secured to the end of sleeve 46 and by suitably manipulatthis crank 1-7, the sleeve it may be moved longitudinally or rotated within the pipe it is held in any desired adjusted position by means of set-screw 48. The sleeve 4A is provided with a series of longitudinally extending slots through which the may pass to reach the exit port 7. As here shown, more particularly in the development of Fig. 7, there are four of these slots 49, 50, 51 and 52. As illustrated, 19 is a c ntinuous straight slot of uniform width. When the sleeve a l is so adjusted as to have slot 49 beneath the row of ports 7, a. continuous and uniform flame is obtained across the entire width of the sheet. By slightly turning the sleeve at one or more rows of ports 7 may be cut oil to diminish the intensity of the flames equally across the width of the sheet. Slot 50 is shown somewhat narrower at the central portion of the sleeve, and slot 51 is narrower at the central portion and also curved outwardly. By suitably adjusting eitl or of these slots :1 flame similar to that shown in Fig. 9, with a diminished intensity at the center of the sheet of glass, could be obtained. Slot 52 has curved portions 53 adjacent the ends thereof. By longitudinally adjusting the sleeve a l either of these curves could be brought over certain side areas of the sheet to partly cut oft the heat at these points. It is to be understood that the form and number of these slots here shown are merely illustrative, and that the number, size and configuration of these slots may be varied as experience may prove desirable.

Projecting into each end ot burner 5 is a rod 54 with an operating handle 55 at its outer end. On the inner end of rod 5 L is mounted a series, here shown as four. of vanes 56, which may be made of various lengths and proportions. The rods 54L are slidable loi'igitudinally, and may be rotated, within the burner 5 so as to bring any vane 56 into register with any desired burner ports 7. As here shown the vanes are mounted within the sleeve 44. When. so used. they would act to partially obstruct but not entirely cut otl' the flow of gas to the burnerholes 7. ll tl vanes 56 were mounted directly within the pipe 5 (the sleeve 14 being omitted), these vanes would act to entirely cut otli' the flow oi gas through such ports as were covered by the vanes. It is to be understood that there is one set of these vanes for each halt oi: burner 5, and by suitably manipulating the knob or handle any desired group of burners in that half of the sheet may be obstructed.

Still another term of controlling means is shown in Fig. 8. In this a sleeve 57 of any suitable length, is slidably and rotarily mounted on the outside of pipe 5.

This sleeve 57 is provided with a. series of slots 58, of any desired configuration, through which the flames may pass, and the remainder of the sleeve between the slots is used to obstruct or cut oil the flow of gas through such of the ports 7 as may be covered by these portions oi the sleeve. Another short slidable member is mounted on pipe 5 adjacent one end of sleeve 57 and provided with a continuous slot or opening 60 whereby this member will not obstruct any oi the openings7. blidable sleeve member 59 provided with a pair of ears 61 in which is mounted a rotary adjusting shaft 62. On the end of shaft 62 is a small gear 63 which meshes with a gear 6% formed on the adjacent end of sleeve 57. A flange 65 on sleeve 57 engaged by slotted projection 66 on sleeve 59 ties the sleeves together for simultaneous longitudinal move ment along pipe 5, but allows relative rotation between the two sleeves.

Adjusting shaft 62 is slidable through bearings 67 adjacent the end of burner 5, and is provided on its end with a. knob or handle 68. By sliding the rod 62 in and out through bearings 67 the sleeve 57 may be adjusted longitudinally along the burner pipe, and by rotating the rod or shaft 62 the sleeve 57 may be rotated around the pipe 5, by means of gears 63 and 6% so as to bring any desired portion of sleeve 57 into register with the ports 7. Adjusting shaft 62 may be locked in any position by setscrew 89.

This form of regulating sleeve 57 may be used alone, or in conjunction with either the sleeve 4:4.- and vanes 56, or with both of them.

To cooperate with the above described improved heating mechanism, an improved form of cooler is provided for use beneath the sheet and bending roller. This cooler 69 is shown in Figs. 1, 2, 10. 11 and 12. The cooler 69 is of a substantial L-shape, and is mounted for swinging adjustment on the horizontal shaft 7 0 carried by the supporting frames 71 adjacent the two ends of the cooler. A lever arm 72 connected with the cooler, is engaged by ascrew 73 vertically adjustable through ear 7 L on supporting frame 71. By suitably adjusting the screw 73 the cooler 69 may be tilted about the shaft to vary its inclination and proximity to the glass sheet 1 and roller 4. A rotary cross-shaft 75 connecting the two frames 71 carries gears 76 which mesh with racks 77 formed in supporting bars 78 on which the frames 71 are slidably mounted.

Cat

By suitably rotating shaft 7 5 the entire cooler assembly may be moved toward or away from the sheet 1.

An internal vane '79 is provided within the angled portion of the cooler body 69, as shown more particularly in Fig. 10, so that the cooling fluid which enters at each end of the cooler through inlet pipes will first be deflected downwardly into the lower end 81 of the cooler and then pass up through channel 82 parallel with the vertical run of the moving sheet. The fluid then passes back through horizontal passage 83 to the rear of the cooler where iteventually passes out through exit pipes 84 at either end. The cold water or other fluid which enters through pipes 80 must first pass through partition member 85, provided with a series of various sized apertures 86 (see Fig. 11). which are so graduated as to be larger or closer together at the central portions of the cooler than adjacent the ends thereof. A similar partition 87 (see Fig. 12), provided with similar apertures 88 is provided at the rear of the cooler adjacent the exit pipes 8%. These apertured partitions will permit and enforce a greater flow of the cooling fluid at the central portion of the cooler than adjacent the ends thereof. This will increase the cooling capacity for the central portion of the cooler where the glass sheet and also the bending roller are usually the hottest and a greater cooling effect is most desired. It will also be noted that the internal vane 79 enforces an upward flow of the cooling tluid adjacent and parallel to the moving sheet so that the maximum cooling effect is obtained from this fluid. In this way a greater and more uniform tensile strength is imparted to the roll-contacting surface of the sheet.

By means of the entire apparatus hereinabove described, the moving glass sheet may be given such a heat treatment adjacent the bending roller that the bending operation may be more easily and satisfactorily accomplished, and the sheet delivered to the flattening mechanism in a much more even and uniform condition than has heretofore been the case.

The improved heater will give an even, blended sheet of flame across the entire width of the sheet. This heater is adjustable so as to vary the proximity of the flames to the sheet and also their angle of contact therewith. All of these adjustments can be easily made from one side of the machine.

This heater can also be controlled to apply the heat locally across the sheet where most desired. If a hot streak develops in any portion of the sheet the application of heat can be cut off or diminished at this point without altering the normal heat applied to other portions of the sheet.

Furthermore by means of the improved cooler, the removal of heat from the lower side of the sheet and bending roller can be varied as occasion demands and a greater cooling effect will always be obtained at. the central portion of the sheet where this treatment is most necessary. This cooler also cts as an effective deflector or shield against the air currents of different temperatures which are usually flowing along the rear of the sheet.

The effect of the cooling and the heating upon the sheet body as the same rounds the bending rpll, if properly applied by the operator, wnl be to produce a sheet of a much flatter extent of body and surface as during its first progression on the horizontal plane after passing over the bending point, the outside surface of the sheet being heated will e):- pand and soften and offer no resistance to the bending operation, while the inner surface of the sheet that is in contact with the roll will-have its rigid properties increased so as to enable it to support the body portion of the sheet without as much sagging as at present. The greater tenacity given to the rear surface layer of the sheet by the cooler will also enable this layer to support the entire sheet area, thus relieving one cause for unequal tension and reducing and combating the tendency of lateral shrinkage of the sheet as the tension of the front surface layer will be largely released by the heating operation.

Claims:

1. The process of reheating a sheet of glass, consisting in applying a series of flames to the sheet surface, and oscillating these flames to equalize the distribution of heat.

2. The process of reheating and equalizing the temperature of a drawn glass sheet prior to the flattening operation, which consists in applying heat along a linetransverse to the moving sheet, and selectively varying the intensity of this heat at local points across the sheet.

3. The process of reheating and equalizing the temperature of a drawn glass sheet prior to the flattening operation, which consists in applying a sheet of flame along a line transverse to the moving sheet, and se lectively varying the intensity of this flame at local points across the sheet.

4. In the drawing of sheet glass, the

method of promoting uniform thickness in a sheet of glass during its-stretching period, which consists in delivering variable degrees of heat to the sheet in a manner to equalize the plasticity of all sections of the sheet area during its plastic forming period.

5. The method of controlling and equalizing the temperatures in a sheet of plasti: glass during drawing over a bending roll, which consists in applying heat to the outside of the sheet along a predetermined zone as it bends over the roll, and in varying the application of the heat so as to equalize the plasticity of the glass body comprising the sheet throughout the sheet area along the bending zone.

(5. The method of controlling and equalizing the temperatures in a sheet of plastic glass during drawing over a bending roll, which consists in applying heat to the outside of the sheet along a predetermined zone as it bends over the roll, and in varying the application of the heat as required so as to equalize the plasticity of the'glass body comprising the sheet throughout the sheet area, while simultaneously removing heat from the opposite side of the sheet prior to its contact with the roll.

7. The method of heat treating a sheet of glass while bending the same, which con sists in applying heat to the outside layer ot the sheet while the side of the sheet which is opposite the heated layer moves in contact with the moving surface of a bending member, and in varying said application of the heat to the sheet so as to apply more heat to all portions thereof which manifest a greater rigidity than adjoining portions, to thereby establish suitable degrees ot like plasticity throughout the intermediate body portion of the sheet area at the bending point.

8. The method of heat treating a sheet of glass while bending the same, which consists in applying heat to the outside layer of the sheet while the side of the sheet which is opposite the heated layer moves in contact with the heat removing surface of a bending member, and in varying said application of the heat to the sheet so as to apply more heat to all portions thereof which manifest a greater rigidity than adjoining portions to thereby establish suitable degrees of like plasticity throughout the intermediate body portion of the sheet area at the bending point, while removing heat from the opposite side of the sheet at a point adjacent said member prior to its contact therewith.

9. In the drawing of sheet glass, the method of correcting unequal pliancy in the sheet, which consists in applying heat to the sheet as it is being drawn in a manner to give a proper degree of heat to each relatively colder or more firm section of the sheet area to thereby give uniform pliant firmness to the plastic sheet body.

10. An apparatus for heating a moving heet of glass, comprising a gas'pipe having a longitudinal series of burner openings, means for supporting the pipe adjacent one face of the sheet and transverse to its direc tion of movement, and means for imparting a longitudinal reciprocating movement to the pipe.

11. The combination with mechanism for contmuouly drawing a sheet of glass vertically from a molten pool, and bending and supporting rollers over which the sheet is deflected into the horizontal plane, of a burner for reheating the sheet adjacent the bending point, and means for oscillating the burner transversely of the sheet.

12. The combination with mechanism for continuously drawing a sheet of glass vertically from a molten pool, and bending and supporting rollers over which the sheet is deflected into the horizontal plane, of a burner for reheating the sheet adjacent the bending point, and means driven from one of the rollers for oscillating the burner transversely oi the sheet.

l3. inn apparatus for heating a moving sheet oi glass, comprising a burner positioned adjacent the sheet 0 as to play thereon, and means for oscillating the burner.

l t. An apparatus for heating a glass sheet comprising a hollow gas container, substantially as long as the width of the sheet, and provided with a longitudinal series of burn er openings, and a plurality of cover-plates selectively movable over certain of the openings.

1.5.An apparatus for heating a. glass sheet comprising a hollow gas container, substantially as long as the width of the sheet, and provided with a longitudinal series of burner openings, and a plurality of cover-plates slidable along the container to selectively close certain of the openings.

16. An apparatus for heating a glass heetcomprising a tubular gas container, substantially as long as the width of the sheet, and provided with a longitudinal series of burner openings, and a plurality of cover-plates rotatable and slidable along the tube for selectively covering certain ot' the openings.

17. An apparatus for heating a glass Fheet comprising a tubular gas container, substantially as long as the width of the sheet, and provided with a longitudinal series of burner openings, a plurality of cover-plates rotatable and .slidable along the tube for selectively covering certain of the openings, and means operable from beyond the end of the tube, for moving any de sired plate into position over the selected opening.

18. An apparatus for heating a glass sheet, comprising a tubular gas container having a longitudinal series of burner openings, and means controllable from the end of the tube for selectably closing certain of the burner openings.

19. An apparatus for heating a. glass sheet, comprising a tubular gas container having a longitudinal series of burner openings, and means for selectably closing certain of the burner openings.

20. An apparatus for heating glass sheet, compri ing a tubular gas container ltltl having a longitudinal series of burner openings, a slotted sleeve within the tube, and means for manipulating the sleeve to selectably close certain of the burner openings.

21. An apparatus for heating a glass sheet, comprising a tubular gas container having a longitudinal series of burner openings, a longitudinally slidable slotted sleeve within the tube, and means for manipulating the sleeve to selectably close certain oi the burner openings.

22. An apparatus for heating a sheet, comprising a tubular container having a longitudinal series of burner openings, a rotatable Slotted sleeve within the tube, and means for manipulating the sleev to selectably close certain of the burner openings.

23. An apparatus for heating a glass sheet, comprising a tubular gas container having a longitudinal series of burner openings, a longitudinali slid-able and rotatable slotted sleeve within the tube, and means for manipulating the sleeve to selectably close certain of the burner'openings.

24. An apparatus for heating a gias'; sheet, comprising a tubular gas container having a longitudinal series of burner openings, a sleeve within the tube having a circumferential series of slots of various configurations extending substantiail lengtlu wise of the tube, and means for rotating the sleeve to selectably bring the slots substantially in alignment with the burner openings.

25, An apparatus for heating a glass sheet, comprising a tubular gas container having a longitudinal series of burner openings, a sleeve within the tube having a circumferential series of slots of various configurations extending substantially lengthwise of the tube, and means for rotating and sliding the sleeve to selectably bring desired portions of the slots substantially in alignment with the burner openings.

26. A cooler for a moving glass sheet, comp "ising a container po itioned transversely of the sheet, means for maintaining a flow of cooling fluid through the container, and bafiie plates within the container to direct a greater portion of the i'lOW oi cooling fluid through the central portion of the container tla through the end portions.

27. A cooler for a moving glass sheet, comprising a container positioned transversely of the sheet, means for maintaining a flow of cooling fluid through the container,

and means for enforcing a flow oi the cooling fluid through the container in the same direction as the moving sheet.

28. The combination with means {or drawing a continuous glass sheet, and a roller about which the sheet is deflected, of a cooler for the sheet and roller, comprising a container oi approximately t e same length as the width of the sheet, means ior maintaining a flow of cooling fluid through the container, and means for adjusting the proximity and inclination of the container with respect to the sheet and roller.

29. The combination with means for drawing a continuous glass sheet, and a roller about which the sheet is deflected, oi a cooler for the sheet and roller, comprising a container of approximately the same length as the width of the sheet, means for maintaining a flow of cooling fluid through the container, and battle plates within the container to entorce a greater flow of the cooling fluid at the central portion of the cooler than at the ends.

Signed at Toledo, in the county of Lucas, and State of Ohio, this 2nd day of October,

ENOCH T. FERNGREN. 

